The present invention relates to a vibration generator, and more particularly, to an apparatus for generating mechanical vibration by combining a rotary drive means having a drive shaft and rotors having unbalanced weights.
In a bustling and complicated modern society, our mental and spiritual stresses, which are induced by anxiety, dissatisfaction, anger, and irritation, are increasing. Accumulation of these stresses may result in symptoms of insomnia including difficulty of sleeping, night awakening, morning awakening, defectiveness of sound sleep feeling, and shortening of sleep. Chronic insomnia may successively cause easy fatigue, malaise, and palpitation, and this results in lowering of mentation and spoiling of concentration of thinking on matters and events, and in some cases even may result in dystrophy and destroy the living of normal social life. The number of insomnia patients is now estimated to be more than several millions mostly in advanced nations.
General method for overcoming insomnia is to take narcotics while receiving professional counseling. Since the actual use of benzoazepine and thienodiazepine hypnotics has been realized, narcotics can be continuously administered to patients for a relatively-long period of time with less fear of considering drug safeness, drug dependency, and drug tolerance. However, narcotics for overcoming insomnia generally require doctor""s prescriptions and could not be used freely at home in general. In view of these difficulties in narcotics, there have been proposed a variety of vibration generators for inducing sleep by vibrating the body. Among these, as disclosed in Japanese Patent Kokai No. 251,278/90, a vibration generator, which comprises a pair of rotors having unbalanced weights provided counteractively each other, a pair of rotary drive means having drive shafts installed in respective rotors, and a phase difference controlling means for electrically regulating the rotary drive means to allow the pair of rotors to rotate at a prescribed phase difference, is known as an apparatus for generating mechanical vibration by combining rotary drive means having drive shafts and rotors having unbalanced weights.
Such a vibration generator, however, has the demerits that it inevitably requires a pair of rotary drive means, and they should be continuously controlled by a phase difference controlling means when operated. In principal, the vibration generator has the difficulty of altering only its amplitude while keeping the vibration frequency at a prescribed level.
The present invention was made to overcome the drawbacks of conventional apparatuses which generate mechanical vibration by combining a rotary drive means having a drive shaft and rotors having unbalanced weights, and aims to provide a vibration generator which requires no phase difference controlling means that electrically controls the rotational phase difference between the rotors.
In addition, the present invention aims to provide a vibration generator which can easily alter only the amplitude while keeping the vibration frequency at a prescribed level.
The present vibration generator, which fulfills the above objects, relates to a vibration generator which comprises a rotary drive means having a drive shaft, a plurality of rotors which are provided on the drive shaft and capable of rotating in association with the drive shaft, and unbalanced weights which are installed in the respective rotors; and more particularly to a vibration generator in which one of the rotors is provided in such a manner that it can rotate against or along the drive shaft.
The present invention also relates to an apparatus for controlling the function of living bodies, which uses the above vibration generator as a vibration source.